首页
登录
职称英语
[originaltext] Why don’t birds got lost on their long migratory flights? Sci
[originaltext] Why don’t birds got lost on their long migratory flights? Sci
游客
2024-02-12
29
管理
问题
Why don’t birds got lost on their long migratory flights? Scientists have puzzled over this question for many years. Now they’re beginning to fill in the blanks.
Not long ago, experiments showed that birds rely on the sun to guide them during daylight hours. But what about birds that fly mainly by night? Tests with artificial stars have proved conclusively that certain night-flying birds are able to follow the stars in their long-distance flights.
One such bird—a warbler—had spent its lifetime in a cage and had never flown under a natural sky. Yet it showed an inborn ability to use the stars for guidance. The bird’s cage was placed under an artificial star-filled sky at migration time. The bird tried to fly in the same direction as that taken by his outdoor cousins. Any change in the position of the make-believe stars caused a change in the direction of his flight.
Scientists think that warblers, when flying in daylight, use the sun for guidance. But the stars are apparently their principal means of navigation. What do they do when the stars are hidden by clouds? Apparently, they find their way by such landmarks as mountain ranges, coast lines, and rivet courses. But when it’s too dark to see these, the warblers circle helplessly, unable to get their bearings.
选项
A、Birds have to be taught to navigate.
B、A bird that has been caged will not.
C、Some birds cannot fly at night.
D、Some birds seem instinctively to follow the stars when flying at night.
答案
D
解析
What do we learn from the experiment with the warbler?
转载请注明原文地址:https://tihaiku.com/zcyy/3445569.html
相关试题推荐
[originaltext]Museumshavechanged.Theyarenolongerplacesforthepriv
[originaltext]Museumshavechanged.Theyarenolongerplacesforthepriv
[originaltext]Museumshavechanged.Theyarenolongerplacesforthepriv
[originaltext]IfyouplantoremainintheUnitedStatesforanylengthof
[originaltext]W:Isupposeyouhaveboughtsomegiftsforyourfamily.M:Well,
[originaltext]W:Isupposeyouhaveboughtsomegiftsforyourfamily.M:Well,
[originaltext]W:Isupposeyouhaveboughtsomegiftsforyourfamily.M:Well,
[originaltext]W:Isupposeyouhaveboughtsomegiftsforyourfamily.M:Well,
[originaltext]W:Isupposeyouhaveboughtsomegiftsforyourfamily.M:Well,
[originaltext]W:Isupposeyouhaveboughtsomegiftsforyourfamily.M:Well,
随机试题
Besidesactiveforeignenterprisesanda【51】numberofprivateemployers,ac
Howlongdoesthistrainingcourselast?[br]Whichcourseshouldyoutakeifyo
【B1】[br]【B15】A、caughtB、sharedC、dividedD、separatedB此题为动词与名词搭配辨析题,也是近义词辨析题。r
Wegenerallyviewthefamilyasbeingoneofourmoststableinstitutions:y
[originaltext]W:Hi,Mr.Brown.How’syourapartmentworkingoutforyou?M:We
人的思想支配人的行为,人的行为不一定反映人的思想。
()扣除通货膨胀补偿以后的利息率。A.固定利率 B.浮动利率 C.实
分包企业签署质量合格的文件上,必须由()的注册建造师签章。A、分包企业 B、
患者,男,60岁。腹胀大如鼓,按之如囊裹水,有波动感应首先考虑的是A.水饮
在GIS数据检查中,利用拓扑关系规则可进行()检查。A:空间数据精度B:空间数
最新回复
(
0
)